^Still, it was an odd choice on the filmmakers' part to have the characters remember a meeting that we never saw in the episode. It can be easily enough rationalized, obviously, but it's still a retcon rather than building on what "Space Seed" actually established, and that's a curious creative decision. Why did they decide to make Chekov the one who recognized Khan? Why not put, say, Uhura or Scotty on the Reliant instead?
This is a great point, Christopher. I think the inclusion of Scotty aboard Reliant
would have made perfect sense given his engineering background. It's entirely plausible that his expertise would have been needed to determine the best way to deploy the Genesis device without endangering the ship once a test site was chosen, so it goes without saying that he should have been included in the site selection process. I suppose the writers wanted to show Chekov in a different role to emphasize the passage of time, but as a navigator and security officer, his presence on a scientific mission would otherwise have been difficult to justify, even knowing the sensitive nature of the Genesis experiment.
Scotty's absence from Enterprise
during the initial confrontation with Khan would have changed the nature of those events, but he still could have been present for the battle in the Mutara Nebula near the film's end.